The Coronary Drug Project (CDP) is a National Heart, Lung and Blood Institute collaborative clinical trial of lipid-influencing drugs in the long-term therapy of coronary heart disease (CHD). Between March 1966 and October 1969, 8,341 men with previous myocardial infarction (MI) were enrolled into the study. Each patient was randomly assigned to one of five drug groups (estrogen at two dosage levels, clofibrate, dextrothyroxine, and nicotinic acid) or a placebo group and was followed in the study until February 1975. Reports on the effects of the five treatments and on various aspects of the natural history of CHD have been published in the medical literature on the basis of data from the CDP. Additional projects involving the analysis of CDP data and the recording of CDP experience and lessons are proposed. Specifically, these projects include: 1. Detailed evaluation of the effects of the study drugs on various biochemical parameters and blood pressure. 2. Investigation of factors associated with the presence and the development of hypertension in post-MI men. 3. Evaluation of the prognostic significance--with respect to mortality and cardiovascular morbidity--of clinically diagnosed recurrent MI and of significant worsensing of ECG patterns on the scheduled annual tracing compared with the baseline ECG. 4. Cost-effectiveness studies of the optimal frequency of ECG recordings and biochemical determinations based on the experience of the CDP. 5. Completion of a 20 chapter monograph on methodological lessons learned in the CDP. Funding is requested for an additional two year period, February 1, 1979 through January 31, 1981, for the CDP Coordinating Center in order to accomplish the tasks listed above.